Method of making slatted plow moldboard



Aug. 28, 1956 R. w. SULLIVAN ETAL 2,760,253

METHOD OF MAKING SLATTED PLOW MOLDBOARD FiledMay 15, 1953 I I I I I I INVENTORS.

'[QoberI W. Sullivan Eugene, V Hudson BY I ATTORNEY United States Patent Ofice 2,760,253 Patented Aug. 28, 1956 METHOD OF MAKING SLATTED PLOW MOLDBOARD Robert W. Sullivan, Van Dyke, and Eugene V. Hudson,

Detroit, Mich, assignors to The Budd Company, Philadelphia, Pa., a corporation of Pennsylvania Application May 15, 1953, Serial No. 355,346

3 Claims. (Cl. 2914) This invention relates to slatted plow moldboards, especially to the method of making the same and has for an object the provision of improvements in this art.

Heretofore some slatted moldboards have been made by attaching slats to a base, as by riveting, welding, or the like. It is difficult to make a smooth even-wearing moldboard by this method.

Some one-piece integral moldboards have been made but it has been very diflicult to make such moldboards with a smooth shape and almost impossible to harden all wearing surfaces evenly. The slats or tines tend to warp in various directions if they are not held by restraining means during heat-treating or hardening steps; and if such slat-restraining means are used there will be certain portions of the articles which are partly or wholly covered by such means and which consequently cannot receive the same effects of heat-treating or hardening as adjacent portions which are more fully exposed.

According to the present invention a slatted moldboard is made as a connected integral unit and maintained as an integral unit until after the final hardened and finished stage is attained. This is accomplished by cutting slots in a blank in the soft state, preferably while flat, and in the process leaving narrow connecting strips of metal between slats to hold them together during further operations. There will be as many connecting stn'ps left as the length of the slats or tines requires and this may depend in part upon the degree of curvature, the nature of the metal, the nature of the treatment to be given, and other factors.

The connecting strips are notched at their ends where they connect with the slats so as to expose as much of the slat surface as possible and to leave such a thin section that it will harden throughout its full thickness to allow the connecting strips to be broken out easily without leaving objectionable scars or rough spots on the edges of the slats at the points of breakage.

After the hardening, shaping and finishing operations on the moldboard have been completed and there is no further need to hold the slats together to maintain the proper moldboard shape, the connecting strips are knocked out to leave the slats separated from each other except at their root ends.

The objects and advantages of the invention will be apparent from the following description of an exemplary embodiment, reference being made to the accompanying drawings, wherein:

Fig. l is plan view of a blank in the flat after being struck by a cutting die;

Fig. 2 is an enlarged cross section taken on the line 2-2 of Fig. 1;

Fig. 3 is a diagrammatic section through a furnace showing a plurality of moldboards in initially shaped form passing through a carburizing furnace;

Fig. 4 is a section through a die set which strikes a carburized blank to give it a final shape;

Fig. 5 is a diagrammatic view of a quenching tank showing a moldboard being quenched after the final shaping operation; and

Fig. 6 is a diagrammatic view showing the frangible connecting strips being knocked out.

As shown in Fig. 1, the moldboard blank 10 comprises a body portion 11 and a number of slats or tines 12. The slats are integral with the body portion 11 and may be formed by cutting slots 13 between the slats, as in a die press. Preferably this cutting operation is performed while the stock is soft and in the flat. The blanks may be cut from a strip of fiat stock, as shown in the copending application of William E. Ruska, S. N. 205,768, filed January 12, 1951, now Patent No. 2,643,438, and assigned to a common assignee of the present applicants.

The die set which cuts the blanks leaves connecting strips 15 between slats. Enough connecting strips 15 are left to keep the moldboard as a whole in shape during subsequent operations. As shown, there is one connecting strip 15 for a short slat and two connecting strips for longer slats.

At an early stage, preferably in the blank-cutting operation, the connecting strips 15 are notched or nicked, as at 16, at each slat to leave a thin section 17 which is just thick enough to hold the parts together but thin enough to harden throughout its full thickness in subsequent operations. The notches 16 have substantially straight sides at each slat, these straight sides coinciding with the side surfaces of the slats.

The blanks are curved, as by being struck in a die press, and are passed through a carburizing furnace 20 to give them a hardenable jacket all over. They may, of course, be of a material which in the stock is hardenable, in which case the carburizing or other surface penetration treatment may be dispensed with.

While still hot, the blanks may be struck, as with shaping dies 22 to give them their final shape.

The shaped blanks, while still hot from the carburizing and re-striking operations, are quenched when they are at the proper temperature, as in a quench bath 24 of oil, water, brine, or whatever agent may be desired, to harden them to the desired depth on all exposed surfaces. The connecting strips 15 and their thin sections 17 at the notches are hardened at the same time. The thin sections 17 will harden throughout their thickness so as to be quite brittle and frangible. They may be knocked out, as by a light blow with a hammer 26, and this is done at this stage after cooling.

The finished moldboards are secured to a plow bottom and the whole working surface may be polished and brightened, painted or finished in the desired manner. In some cases the slats may be strengthened in known manner by a strap or other support secured to their upper ends where it will not interfere with the flow of earth over the slats. After the connecting strips 15 have been knocked out the slat sides may be ground at the points of separation if any objectionable roughness is left after breakage. Usually this will not be necessary. The points of breakage are hard because the sections 17 at the notches were left so thin that penetration is possible. The penetration into the side of the slat at the breakage point is not as deep as elsewhere.

It is seen that the invention provides an improved method of making slatted moldboards and that an improved product results from the practice of the method. The desired shape is maintained throughout all operations and the final moldboard is free from the usual warped slats. The slats are all hard on all surfaces, as is the body portion of the mold-board and in service the wear will be as even and uniform over the entire surface as is normally possible with a full-bladed moldboard. In addition, the method is very simple and inexpensive to practice and requires only simple equipment.

While one embodiment of the invention has been de scribed for purposes of illustration, it is to be understood that there may be various embodiments within the general scope of the invention.

What is claimed is:

1. The method of making a slatted moldboard which comprises, forming a moldboard blank with slats conn'e'cted at intervals by integral strips with reduced sections at both ends of each connecting strip, shaping and hardening the moldb'oard, and breaking out the slatconnecting strips.

2. The method of making a slatted moldboard which compn'ses, forming a moldboard blank with slats integrally connected to a base portion and with integral strips connecting the slats at intervals, notching the connecting strips at their slat-connected ends to leave thin sections, shaping and hardening the moldboard to harden the thin connecting sections throughout their thickness, and breaking out the slat-connecting strips at the notched sections thereof.

3. The method of making a slatted moldboard which comprises, cutting in the flat from soft steel stock a blank having spaced slats integral at their roots with a base *portion and connecting strips integral With the slats at intervals to leave the moldboard as a connected web, at the same time notching the connecting strips from each face at their ends to leave thin sections with the notches left straight at the slat ends, initially shaping the moldboard blank, carbnrizing the blank on all surfaces to form a complete jacket to a depth sufiicient to at least penetrate the full thickness of said connecting sections, re-striking the blank while hot, quenching the blank to harden it and form a complete hard jacket thereover, and breaking out the hardened connecting strips at their thin notched sections at the ends connected to the slats.

References Cited in the file of this patent UNITED STATES PATENTS 1,604,264 Donnan Oct. 26, 1926 2,043,619 Henley June '9, 1936 2,291,722 Ingersol Aug. 4, 1942 2,325,079 Soderholm July 27, 1943 2,643,438 Ruska June 30, 1953 2,668,131 Hamm Feb. 2, 1954 

